A new ankylosaurid (Dinosauria: Ankylosauria) from the Lower Cretaceous of China, with comments on ankylosaurian relationships

2001 ◽  
Vol 38 (12) ◽  
pp. 1767-1780 ◽  
Author(s):  
Matthew K Vickaryous ◽  
Anthony P Russell ◽  
Philip J Currie ◽  
Xi-Jin Zhao
Keyword(s):  
Phylogenetic Analysis ◽  
Lower Cretaceous ◽  
Sister Taxon ◽  
Taxonomic Assignment ◽  
Fossil Material ◽  
Preliminary Phylogenetic Analysis

Amongst the fossil material collected by the Sino-Soviet Expeditions (1959–1960) to the Alshan Desert, China, was a large, virtually complete ankylosaur skeleton. Gobisaurus domoculus gen. et sp. nov. closely resembles Shamosaurus scutatus, but is distinct in having an unfused basipterygoid–pterygoid contact and elongate premaxillary processes of the vomers. Although it is difficult to make a definitive taxonomic assignment without considering postcranial material, a preliminary phylogenetic analysis places Gobisaurus as the sister taxon of Shamosaurus, clustered as one of several successive outgroups of the Ankylosaurinae.

scholarly journals The systematic position of the enigmatic thyreophoran dinosaurParanthodon africanus, and the use of basal exemplifiers in phylogenetic analysis

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4529 ◽  
Author(s):  
Thomas J. Raven ◽  
Susannah C.R. Maidment
Keyword(s):  
South Africa ◽  
Phylogenetic Analysis ◽  
Lower Cretaceous ◽  
Phylogenetic Analyses ◽  
Systematic Position ◽  
Type Material ◽  
Sister Taxon ◽  
Phylogenetic Position ◽  
Taxonomic Assignment

The first African dinosaur to be discovered,Paranthodon africanuswas found in 1845 in the Lower Cretaceous of South Africa. Taxonomically assigned to numerous groups since discovery, in 1981 it was described as a stegosaur, a group of armoured ornithischian dinosaurs characterised by bizarre plates and spines extending from the neck to the tail. This assignment has been subsequently accepted. The type material consists of a premaxilla, maxilla, a nasal, and a vertebra, and contains no synapomorphies of Stegosauria. Several features of the maxilla and dentition are reminiscent of Ankylosauria, the sister-taxon to Stegosauria, and the premaxilla appears superficially similar to that of some ornithopods. The vertebral material has never been described, and since the last description of the specimen, there have been numerous discoveries of thyreophoran material potentially pertinent to establishing the taxonomic assignment of the specimen. An investigation of the taxonomic and systematic position ofParanthodonis therefore warranted. This study provides a detailed re-description, including the first description of the vertebra. Numerous phylogenetic analyses demonstrate that the systematic position ofParanthodonis highly labile and subject to change depending on which exemplifier for the clade Stegosauria is used. The results indicate that the use of a basal exemplifier may not result in the correct phylogenetic position of a taxon being recovered if the taxon displays character states more derived than those of the basal exemplifier, and we recommend the use, minimally, of one basal and one derived exemplifier per clade.Paranthodonis most robustly recovered as a stegosaur in our analyses, meaning it is one of the youngest and southernmost stegosaurs.

scholarly journals The systematic position of the enigmatic thyreophoran dinosaur Paranthodon africanus, and the use of basal exemplifiers in phylogenetic analysis

2018 ◽  
Author(s):  
Tom Raven ◽  
Susannah C. R. Maidment
Keyword(s):  
South Africa ◽  
Phylogenetic Analysis ◽  
Lower Cretaceous ◽  
Phylogenetic Analyses ◽  
Systematic Position ◽  
Type Material ◽  
Sister Taxon ◽  
Phylogenetic Position ◽  
Taxonomic Assignment

The first African dinosaur to be discovered, Paranthodon africanus was found in 1845 in the Lower Cretaceous of South Africa. Taxonomically assigned to numerous groups since discovery, in 1981 it was described as a stegosaur, a group of armoured ornithischian dinosaurs characterised by bizarre plates and spines extending from the neck to the tail. This assignment has been subsequently accepted. The type material consists of a premaxilla, maxilla, a nasal, and a vertebra, and contains no synapomorphies of Stegosauria. Several features of the maxilla and dentition are reminiscent of Ankylosauria, the sister-taxon to Stegosauria, and the premaxilla appears superficially similar to that of some ornithopods. The vertebral material has never been described, and since the last description of the specimen, there have been numerous discoveries of thyreophoran material potentially pertinent to establishing the taxonomic assignment of the specimen. An investigation of the taxonomic and systematic position of Paranthodon is therefore warranted. This study provides a detailed re-description, including the first description of the vertebra. Numerous phylogenetic analyses demonstrate that the systematic position of Paranthodon is highly labile and subject to change depending on which exemplifier for the clade Stegosauria is used. The results indicate that the use of a basal exemplifier may not result in the correct phylogenetic position of a taxon being recovered if the taxon displays character states more derived than those of the basal exemplifier, and we recommend the use, minimally, of one basal and one derived exemplifier per clade. Paranthodon is most robustly recovered as a stegosaur in our analyses, meaning it is one of the youngest and southernmost stegosaurs.

An unusual new basal iguanodont (Dinosauria: Ornithopoda) from the Lower Cretaceous of Teruel, Spain

Zootaxa ◽  
2012 ◽  
Vol 3595 (1) ◽  
pp. 61 ◽  
Author(s):  
ANDREW T. MCDONALD ◽  
EDUARDO ESPÍLEZ ◽  
LUIS MAMPEL ◽  
JAMES I. KIRKLAND ◽  
LUIS ALCALÁ
Keyword(s):  
Phylogenetic Analysis ◽  
Lower Cretaceous ◽  
Fossil Record ◽  
New Taxon ◽  
Unique Combination ◽  
Preliminary Phylogenetic Analysis

We describe a new basal iguanodont, Proa valdearinnoensis, from the Lower Cretaceous (lower Albian) EscuchaFormation of Teruel Province, Spain. The new taxon is known from abundant cranial and postcranial material belongingto several individuals, and is distinguished by an autapomorphy (predentary comes to a point at its rostral margin, withdivergent lateral processes) and a unique combination of characters. Proa fills part of an otherwise lengthy temporal gap(early Aptian–Santonian) in the European fossil record of basal iguanodonts. A preliminary phylogenetic analysis placesProa in a polytomy with Iguanodon bernissartensis and more derived iguanodontians (Hadrosauroidea). Proa is morebasal than the Valanginian Hypselospinus and late Barremian-early Aptian Mantellisaurus, suggesting a long ghost lineage leading to Proa.

scholarly journals Microcleidus melusinae, a new plesiosaurian (Reptilia, Plesiosauria) from the Toarcian of Luxembourg

2017 ◽  
Vol 156 (1) ◽  
pp. 99-116 ◽  
Author(s):  
PEGGY VINCENT ◽  
ROBERT WEIS ◽  
GUY KRONZ ◽  
DOMINIQUE DELSATE
Keyword(s):  
Phylogenetic Analysis ◽  
United Kingdom ◽  
Early Jurassic ◽  
Sister Taxon ◽  
Morphological Disparity ◽  
The United Kingdom ◽  
High Degree ◽  
Preliminary Phylogenetic Analysis

AbstractMost of the known and most-complete Early Jurassic specimens of plesiosaurians were recovered from the United Kingdom and Germany, and few specimens from that age originate from other areas in Europe. This study describes a new plesiosaurian taxon from Toarcian deposits of Luxembourg,Microcleidus melusinae, represented by the most complete skeleton ever discovered from this country. A preliminary phylogenetic analysis placesMicrocleidus melusinaewithin Microcleididae, as a sister taxon of the species previously included in the genusMicrocleidus. The new specimen studied here contributes to our understanding of the palaeodiversity of Early Jurassic plesiosaurians and confirms their high degree of ‘endemism’ and low morphological disparity.

scholarly journals Evolutionary significance of the blastozoan Eumorphocystis and its pseudo-arms

2020 ◽  
pp. 1-17
Author(s):  
Thomas E. Guensburg ◽  
James Sprinkle ◽  
Rich Mooi ◽  
Bertrand Lefebvre
Keyword(s):  
Phylogenetic Analysis ◽  
Sister Taxon ◽  
Evolutionary Significance ◽  
Coelomic Cavity ◽  
Anatomical Features ◽  
New Findings ◽  
Solid Block ◽  
Cover Plates

Abstract Twelve specimens of Eumorphocystis Branson and Peck, 1940 provide the basis for new findings and a more informed assessment of whether this blastozoan (a group including eocrinoids, blastoids, diploporites, rhombiferans) constitutes the sister taxon to crinoids, as has been recently proposed. Both Eumorphocystis and earliest-known crinoid feeding appendages express longitudinal canals, a demonstrable trait exclusive to these taxa. However, the specimen series studied here shows that Eumorphocystis canals constrict proximally and travel within ambulacrals above the thecal cavity. This relationship is congruent with a documented blastozoan pattern but very unlike earliest crinoid topology. Earliest crinoid arm cavities lie fully beneath floor plates; these expand and merge directly with the main thecal coelomic cavity at thecal shoulders. Other associated anatomical features echo this contrasting comparison. Feeding appendages of Eumorphocystis lack two-tiered cover plates, podial basins/pores, and lateral arm plating, all features of earliest crinoid ‘true arms.’ Eumorphocystis feeding appendages are buttressed by solid block-like plates added during ontogeny at a generative zone below floor plates, a pattern with no known parallel among crinoids. Eumorphocystis feeding appendages express brachioles, erect extensions of floor plates, also unknown among crinoids. These several distinctions point to nonhomology of most feeding appendage anatomy, including longitudinal canals, removing Eumorphocystis and other blastozoans from exclusive relationship with crinoids. Eumorphocystis further differs from crinoids in that thecal plates express diplopores, respiratory structures not present among crinoids, but ubiquitous among certain groups of blastozoans. Phylogenetic analysis places Eumorphocystis as a crownward blastozoan, far removed from crinoids.

Revisiting the type of Cespitularia stolonifera Gohar, 1938 leads to the description of a new genus and a species of the family Xeniidae (Octocorallia, Alcyonacea)

Zootaxa ◽  
2021 ◽  
Vol 4964 (2) ◽  
pp. 330-344
Author(s):  
YEHUDA BENAYAHU ◽  
LEEN P. VAN OFWEGEN ◽  
J. P. RUIZ ALLAIS ◽  
CATHERINE S. MCFADDEN
Keyword(s):  
Phylogenetic Analysis ◽  
New Genus ◽  
Soft Coral ◽  
Taxonomic Assignment ◽  
Coral Genus ◽  
The Family ◽  
Molecular Phylogenetic ◽  
Membranous Part ◽  
Green Island ◽  
A New Species

Because of the problematical identity and status of the type of the xeniid soft coral genus Cespitularia Milne-Edwards & Haime, 1850, the species C. stolonifera Gohar, 1938 is revised. Examination of the type colonies has led to the establishment of the new genus Unomia gen. n. which is described and depicted. This genus features a stalk, commonly divided into branches featuring a diffuse polypiferous part consisting of distal clustered polyps and proximal individual ones on the stalk or the basal membranous part of the colonies. The sclerites are ellipsoid platelets composed of dendritic calcite rods whose tips are distinct on the surface of the platelets. Freshly collected material from Venezuelan reefs where the species is invasive was subjected to molecular phylogenetic analysis, the results of which substantiate the taxonomic assignment of the new genus under U. stolonifera comb. n. A new species, U. complanatis, from Japan and Green Island (Taiwan) is described and further illustrates the extent of the interspecific morphological variation within the genus. The results reveal that the biogeographic distribution of Unomia gen. n. includes Pacific Ocean reefs in addition to the previously reported invaded Caribbean reefs. 

scholarly journals A new iguanodontian (Dinosauria: Ornithopoda) from the Early Cretaceous of Mongolia

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5300
Author(s):  
Terry A. Gates ◽  
Khishigjav Tsogtbaatar ◽  
Lindsay E. Zanno ◽  
Tsogtbaatar Chinzorig ◽  
Mahito Watabe
Keyword(s):  
Phylogenetic Analysis ◽  
Growth Stage ◽  
Phylogenetic Analyses ◽  
Type Specimen ◽  
Sister Taxon ◽  
New Taxon ◽  
Time Of Death ◽  
The North ◽  
Unusual Combination ◽  
Relationship Of

We describe a new iguanodontian ornithopod,Choyrodon barsboldigen. et sp. nov. from the Albian-aged Khuren Dukh Formation of Mongolia based on several partial skeletons interpreted to represent a subadult growth stage based on osteohistological features. This new taxon is diagnosed by many autapomorphies of the maxilla, nasal, lacrimal, opisthotic, predentary, and surangular.Choyrodondisplays an unusual combination of traits, possessing an open antorbital fenestra (a primitive ornithopod trait) together with derived features such as a downturned dentary and enlarged narial fenestra. Histological imaging suggests that the type specimen ofChoyrodonwould have been a subadult at the time of death. Phylogenetic analysis of two different character matrices do not positChoyrodonto be the sister taxon or to be more primitive than the iguanodontianAltirhinus kurzanovi, which is found in the same formation. The only resolved relationship of this new taxon is that it was hypothesized to be a sister-taxon with the North American speciesEolambia caroljonesa. Though discovered in the same formation andChoyrodonbeing smaller-bodied thanAltirhinus, it does not appear that the former species is an ontogimorph of the latter. Differences in morphology and results of the phylogenetic analyses support their distinction although more specimens of both species will allow better refinement of their uniqueness.

A new Xenungulata (Mammalia) from the Paleocene of Patagonia, Argentina

2008 ◽  
Vol 82 (2) ◽  
pp. 329-335 ◽  
Author(s):  
Javier N. Gelfo ◽  
Guillermo M. López ◽  
Mariano Bond
Keyword(s):  
Phylogenetic Analysis ◽  
South America ◽  
Phylogenetic Relationship ◽  
New Taxon ◽  
Parsimonious Tree ◽  
Late Paleocene ◽  
Direct Association ◽  
Mammalian Faunas ◽  
New Form ◽  
Preliminary Phylogenetic Analysis

A new form of Xenungulata Paula Couto, 1952 from red levels of the Peñas Coloradas Formation in a locality near Puerto Visser (45°17'S, 67°01'W), Chubut province, Argentina, is represented by a fragmentary left jaw with the m3 (MPEF-PV 1871). Notoetayoa gargantuai n. gen. and n. sp. is the first ever found in direct association with Carodnia feruglioi Simpson, 1935a which characterizes the incompletely known homonymous zone of the late Paleocene of Patagonia. A preliminary phylogenetic analysis, including representatives of “Condylarthra,” Litopterna, Notoungulata, Pyrotheria, Xenungulata and Astrapotheria, plus the characters that could be scored in the new taxon, was performed using TNT software. A single most parsimonious tree was obtained. Notoetayoa gargantuai has a closer phylogenetic relationship with the Xenungulate Etayoa bacatensis Villarroel, 1987 from the ?middle Paleocene of Colombia than with any other Tertiary ungulate group of South America. Notoetayoa gargantuai fills an important gap in the knowledge of the mammalian faunas from the Paleocene of Patagonia, particularly of the poorly known pre-Itaborian times.

Tanaidacea (Crustacea: Peracarida) from Japan. IV. Shallow-water species from Akajima with notes on the recolonization potential of tanaids

Zootaxa ◽  
2008 ◽  
Vol 1678 (1) ◽  
pp. 1 ◽  
Author(s):  
KIM LARSEN ◽  
MICHITAKA SHIMOMURA
Keyword(s):  
Phylogenetic Analysis ◽  
Shallow Water ◽  
New Genus ◽  
Abundant Species ◽  
Two New Species ◽  
Sandy Habitat ◽  
Nansei Islands ◽  
Shallow Water Species ◽  
Water Species ◽  
Preliminary Phylogenetic Analysis

Two new species of tanaids were collected from colonization traps deployed in a shallow water, sandy habitat off Akajima, Nansei Islands. One new parapseudidaen, Parapseudes arenamans, and one new nototanaidaen genus and species, Paranesotanais longicephalus, are described herein. A preliminary phylogenetic analysis of the closest genera confirms the validity of the new genus and suggests a close affinity between the Leptocheliidae and Nototanaidae. Paranesotanais longicephalus was by far the most abundant species in the habitat. Parapseudes arenamans is faster in colonization of vacant substrate (opportunistic species), while being an inferior competitor to Paranesotanais longicephalus later in succession. A key to Nesotanais and Paranesotanais is provided.

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